This invention relates to a method for rapidly locating a malfunctioning brake control valve that is causing an undesired emergency brake application to occur.
It is a well-known fact that freight trains can be as much as one mile or more in length. Accordingly, when a brake control valve malfunctions, it causes the brakes on the entire train to apply full emergency pressure and the entire train stops. The train crew must endeavour to find the car which has the malfunctioning brake control valve. In addition, the entire train must be walked from one end to the other and visually inspected to assure that no damage has been done during the emergency stop, or that there is no reason other than a malfunctioning brake control valve, to have caused the emergency brake application.
When the car with the malfunctioning brake control valve is located, the brakes in this car can be deactivated by closing a cock in the branch pipe from the main brake pipe to the brake control valve. At the first opportunity, the car with the malfunctioning control valve can be switched out of the train and repaired. However, means presently available to locate a malfunctioning brake control valve that is causing undesired emergency brake applications are restricted to very time-consuming procedures such as the one outlined below:
1. Close the angle cock on the brake pipe at approximately the middle of the train when the train is stationary. This will isolate the cars to the rear of the point where the angle cock is closed.
2. Make a brake application with the brake valve located in the operating cab of the locomotive. If the malfunctioning brake control valve is located in front of the point at which the angle cock was closed, it will initiate undesired emergency brake application. However, if the malfunctioning brake control valve is located in the rear portion, no emergency undesired application will result.
3. Assuming that a malfunctioning brake control valve is in the section of train in front of the point at which the angle cock was closed, it is then necessary to continue closing angle cocks and making brake applications gradually isolating sections of the train until such time as the car with the malfunctioning brake control valve is found. It must be realized that a malfunctioning brake control valve that is causing undesired emergency brake application cannot be found by mere visual inspection. It should, therefore, be appreciated that much time would be saved if some technique could be devised for indicating the malfunctioning brake control valve either on the road or after arrival at an intermediate terminal.